bio set 4 (2).txt

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bio set 4 (2).txt
2011-03-28 08:38:26
bio set

bio set 4
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  1. # Why are integral proteins embedded into membranes?
    Because they have alot of hydrophobice amino acid side chains. Membranes are hydrophobic by nature.
  2. # How can you get an intergral membrane protein out of the membrane?
    By adding a ionic detergent, it will "wash" the protein out of the membrane so it can be viewed independently.
  3. # Which detergent will get a membrane protein out of the membrane? a nonionic or a ionic?
  4. # What detergent are we going to use?
    ionic detergent = SDS
  5. # What are we assuming the SDS-PAGES's charge is in this class?
  6. # What is the point of ripping a membrane protein out of a membrane?
    To get in solubilized in the water
  7. # What is the starting material for membrane proteins
  8. # What are the only membrane that mature RBCs have?
    Plasma membranes
  9. # Why were the RBCs looked at first?
    Because they only consists of a plasma membrane and nothign else (no ers, golgi, etc.)
  10. # How do you get to study the plasma membrane of an RBC and nothign else?
    By "popping" it and getting the "ghost"
  11. # How do you get the RBC "ghosts?"
    Hemolysis (pop and reseal after osmotic shock)
  12. # The hemolysis of a RBC is hypotonic or hypertonic?
  13. # How do you physically just get the ghosts of the RBC?
    Preform hemolysis on the RBCs, centrifuge it, then throw out the supernatant (goo inside), to leave the "ghosts"- plasma membrane
  14. # RBC ghosts are _____ plasma membranes
  15. # If you want to know what pure plasma membrane are you need to study the ...
    RBC ghosts
  16. # If you add SDS-PAGE to the RBC ghosts what will it do to them?
    rip the membrane proteins out of the membrane, and cover them in detergent
  17. # "top of the gel" means
    Where we started the experiment
  18. # When SDS-PAGE is added to a membrane, what proteins come off? Peripheral or integral?
    Both of them, peripheals are easily washed away and integrals are ripped out by the detergent.
  19. # what is your first assumption about membrane proteins?
    That they are all negatively charged and all soluble.
  20. # How do you start the electrophoresis?
    By turning on the electricity and having the proteins pull towards the positive pole (because proteins *are negative* opposites attract)
  21. # How do we know when to turn off the electricity for the electrophoresis?
    When the proteins hit the colored dye at the "bottom"
  22. # How would you determine which proteins are peripheal and which are integral in gel electrophoresis?
    Cetrifuge the RBC ghosts in a high salt solution. then re-do the gel electrophoresis. Peripheal proteins will have come off due to the high salt, and all that is left is the intergral proteins.
  23. # How would you know what the molecular weight of certian proteins are?
    By indicating bands with known molecular weights.
  24. # You can identify a protein by its...
    molecular weight
  25. # With SDS coating proteins, they move by ___________ towards the _________ pole.
    • * electrophoresis
    • * positive
  26. # The smaller proteins move ________ in electrophoresis
  27. # What is electrophoresis used for?
    Which proteins are integral and which are peripheral.
  28. # What is Actin?
    • * A long fibrous protein
    • * peripheal protein
    • * CytoSkeleton like
    • * Ties together integral protiens
    • * (cytoskeletal filaments)
  29. # Sugars are on the...
    outside of the cell
  30. # You will only see what three things facing the outside of the cell?
    • * Sugars
    • * Glycolipids
    • * Glycoproteins
  31. # All cytofilaments are ....
    polymers of proteins
  32. # Cytofilaments are assembled from a pool of protein subunits and ___________.
  33. # Each protein is a polymer of...
    amino acid
  34. # Polymerize proteins to make a....
  35. # Filament means...
    a polymer of proteins
  36. # Protein subunits start as monomers and are polymerized to....
  37. # protein filaments are depolymerizied into
    monomeric subunits
  38. # If a cell wants to divide what must they do to the cytofilaments?
    depolymerize them
  39. # Some filaments are _________, always changing by assembly and disassembly
  40. # If filaments grow more than they shrink they get ....
  41. # If filaments shrink more than they grow they get...
  42. # What are the three main kinds of cytoskeletal filaments?
    • * microtubules
    • * intermediate filaments
    • * microfilaments
  43. # What is the typical diameter size of a microtubules?
    25 nm
  44. # What is the typical diameter size of a intermediate filaments?
    10 nm
  45. # What is the typical diameter size of a microfilaments?
    5-7 nm
  46. # How can you theorectially tell which cytoskeltal filament is which?
    By cutting them and measuring the diameter of it.
  47. # What are microtubules?
    • * A "tube of tubulin"
    • * Tubulin subunits are dimers (heterodimers)
    • * heterodimers made of Alpha tubulin and Beta tubulin
  48. # In a microtubules, aplha and beta tubulins _________ to make the dimers.
  49. # Do you need atp for alpha and beta tubulins to spontaneously form micrtobules in vitro?
  50. # what is the main idea behind intermediate filaments?
    that you can put many of them together and just end up with one big intermediate filaments
  51. # Microfilaments are made of..
  52. # What does Micofilaments, actin filaments, f-actin and filamentous actin have in common?
    they are all the same thing
  53. # Actin monomers are...
    just actin
  54. # if you put actin monomers together by polymerization you get...
    Filament (polymer)
  55. # How do filaments become stronger?
    By turning into a double helix of filaments
  56. # When we say microfilaments is really means the...
    double helix of filaments
  57. # Globular actin is not just a glob because
    it has structure to it
  58. # ATP is required to make what kind of filaments?
  59. # GTP is required to make what kind of filaments?
  60. # "various globular proteins" are needed to make what kind of filament?
    intermediate filaments
  61. # What End are microtubules built on?
    The "+" end
  62. # Where are intermediate filaments built on?
    internal (all over the place)
  63. # What end do microfilaments grow on?
    the "+" end
  64. # Do microtubules have polarity?
  65. # Do intermeidate filaments have polarity?
  66. # do microfilaments have polarity?
  67. # What does a GTPase do?
    breaks down GTP
  68. # What does a ATPase do?
    breaks down ATP
  69. # What is the enzymatic activity of microtubules?
  70. # what is the enzymatic activity of intermediate filaments?
  71. # what is the enzymatic activity for microfilaments?
  72. # What are microtubules motor proteins?
    Kinesins, dyneins
  73. # what are microtubules motor proteins?
  74. # what are intermeidate filaments motor proteins?
    they have none
  75. # What are the microtubules major group of associated proteins?
  76. # What are the major group of associated proteins for microfilaments?
    Actin-binding proteins
  77. # What is the structure of microtubules?
    Stiff, hollow tube
  78. # What is the structure of intermediate filaments?
    tough, ropelike fibers
  79. # What is the structure of microfilaments?
    flexible, helical filament
  80. # Who has microtubules?
    all eukaryotes
  81. # Who has intermediate fibers?
    only animals
  82. # who has microfilaments?
    all eukaryotes
  83. # What is the primary function of microtubules?
    • * MAINLY intracellular transport
    • * Support
    • * Cell Organization
  84. # What is the primary function of intermediate filaments?
    structural support
  85. # What is the primary fuction of microfilaments?
    Motility, contractility
  86. # The molecular weights of intermediate fibers are usually...
    all over the place
  87. # What would pure microtubules look like on SDS-PAGE w/high salt?
    two seperate bands (alpha and beta tubulin)
  88. # what is the genral molecular weight of the tubulins in pure microtubulins on SDS-PAGE?
    about 66 kDa
  89. # What would microfilaments look like on SDS-PAGE w/high salt?
    One band of actin
  90. # What is the general molecular weight of the actin in microfilaments on SDS-PAGE?
    about 43 kDa
  91. # SDS breaks down everything into it's __________ form.
  92. # How do you use SDS-PAGE to identify a protein?
    It's size againt the molecular standards
  93. # How can you stop cell division?
    Stop microtubules from growing
  94. # Microtubules are repeating units of ....
    heterodimers (alpha and beta)
  95. # what is the tubulin dimer?
    The subunit for the protofilament
  96. # What is a protofilament?
    One line of tubulin
  97. # Protofilaments form...
  98. # Tubulin dimers, microtubules are _________, no need to add energy.
    spontaneous, they form on their own.
  99. # In microtubules, alpha is on the _______ end.
  100. # in microtubules, beta is on the ________ end.
  101. # Microtubles always grow at the ______ end.
  102. # Does GTP hydrolysis is microtubles provide energy?
  103. # The complete formation of a microtubule is?
    • * The alpha and beta forms a tubulin dimer
    • * The tubulin dimer forms a protofilament
    • * 13 protofilaments form a microtubule
  104. # Microtubule is ...
    A clynider made of 13 protofilaments side by side (cytoplasmic)
  105. # If you preform a cross section on a microtubule how many protofilaments would you see?
  106. # Is GTP hydrolysis necessary for the Microtubule to grow?
  107. # Colchicine inhibits _________.
    Microtubule growth
  108. # what is the role of GTP in microtubule assembly?
    To allow protofilaments to grow
  109. # What are the three binding site on the beta of a tubulin dimer?
    • * Ca ++ binding site
    • *Colchine Binding Site
    • * Exchangeable GTP Binding Site
  110. # You cannot add to a protofilament unless the beta in the last tubulin dimer has..
  111. # Charged tubulin is?
    Tubublin that is GTP bound.